Agricultural harvesting machines such as combine harvesters generally are developed to handle a large variety of crops. For example a combine harvester may be used to harvest small grain crops such as wheat and rye, or grass seed or large grain crops such as peas or corn. In this manner the use of the harvester, which is a high investment tool, can be extended over a longer season.
Conventionally, the harvester is equipped with a detachable crop collecting attachment, such as a grain or corn header, which cuts the stems of the crop standing in the field and conveys the same to the inlet by a material moving system. Alternatively crop which has been cut previously can be lifted up from the field by a pick-up attachment and conveyed to the same inlet. The material moving system, commonly a chain elevator with transverse slats, pick up the collected crop deposited in front of the inlet and convey it rearwardly and upwardly towards the crop processing mechanism, conventionally a threshing drum and concave or grate assembly.
The transverse slats of the elevator must be structurally robust because of the increasing capacity of modern harvesters. Foreign objects, such as rocks, pieces of timber, or other objects conveyed to the inlet of the material moving system along with crop material can cause an abrupt seizure of the material movement system. Such seizures subject the slats to significant loads which may result in a permanent deformation of the slats.
In response, to increase their strength, the slats may be made out of a more complicated profile, such as an H-shaped profile constructed from opposed U-shaped portions joined together as shown in U.S. Pat. No. 7,473,168. However, slats having an H-shaped profile remain susceptible to problems associated with abrupt seizures of the material moving system caused by introduction of foreign objects. That is, one U-shaped portion of the H-shaped slat profile encounters the foreign object, with the foreign object becoming wedged against one side of a structure of the material moving system, and the opposed U-shaped portion of the H-shaped slat profile wedged against an opposed side of the structure of the material moving system.
One technique typically utilized by an operator in an attempt to dislodge the foreign object is to halt forward movement of the agricultural harvesting machine and attempt to reverse the direction of movement of the material moving system. However, due both to both legs of the U-shaped portion of the H-shaped profile being brought into wedged contact with the structure of the material moving system, the material moving system is immobilized, with such reverse movement forces often being insufficient to overcome the wedged condition. As a result, the operator is forced to try to remove the foreign object manually, which first requires manually clearing out crop material from the material moving system prior to being able to access the foreign object. Such manual effort is time-consuming, requiring a high degree of exertion by the operator, and otherwise highly undesirable.
Accordingly, there is a need for a structurally robust slat construction having an anti-wedge capability to help dislodge foreign objects from the material moving system.